Process of treating fibrous material



Patented 'Jan. 1-, 1929.

UNITED. STATES PATENT OFFICE.

JAMES MCIN'IOSH, OF vNORRISCllOVVN, PENNSYLVANIA, ASSIGNOR TO DIAMONDSTATE FIBRE COMPANY, F BRIDGEPORT, PENNSYLVANIA-7., A CORPORATION OFDELA WARE.

PROCESS TREATING FIBROUS"MATER IAL.

N0 Drawing.

One object of my invention is to prepare a fibrous material which wil bewater-resistant. and mechanically strong and will have a hard,'s1 nooth,lustrous surface.

5 Another object is to provide a means of covering a fibrous materialwith a transparent, colorless and highly polished coatit further objectof my invention is to make a laminated material which willbewater-proof, mechanically strong, hard, compact, and relativelyinexpensive to make.

Anotherobject of my invention is to provide a novel means for preparingthe above product.

The product comprising my invention broadly comprises fibrous material,which has been impregnated with a solution of acellulose ester andsubsequently subjected to heat and pressure.

The fibrous sheets may be made of any of the large class of substanceswhich, when passed through a bath of the cellulose ester, will absorbthe solution Paper, textile fabrics, fibre board, and asbestos sheetshave proved to be satisfactory.

The term cellulose ester embraces that class of compounds which areformed by the action of; acids on cellulose, and includes the celluloseacetates and cellulose nitrates. Due to the non-inflammable nature ofcellulose acetate, I prefer to use this compound. It may be dissolved inany solvent desired, such as alcohol, acetone, acetic acid, chloroform,acetylenetetrachloride.

The fibrous material to be impregnated is passed through the bath of thecellulose ester in the solvent, whereupon the solution is absorbed. Thesolvent is then usually evaporated by passing the sheets overheatingcoils at a temperature sufliciently high to volatilize the solvent butnot high enough to cause the cellulose acetate to fuse. a

Theimpregnated fibrous material is then ready to be vulcanized, that1'sto be subjected to heat and pressure. .The single sheets, if they areof the desired thickness", are vulcanized per se, or a laminated productis built up bv superimposing one sheet upon another until the requisitethickness is obtained. In

either case. the vulcanization is accom-' plished inthe same manner.

Thesheets are placed between the heated Application filed January 30,192 6. Serial No. 85,021.

platens of a suitable press whereby they are subjected to pressure suchas one thousand pounds per square inch at a temperature of one hundredand twenty-five pounds of steam.

This heat and pressure are maintained for a time sufficient to cause thecellulose ester to fuse throughout the fibrous mass and to flowcompletely over the surface forming a continuous. coating. If theplatens are highly polished, there will result a smooth, uniform andhighly the surface of the fibrous material.

Since the cellulose ester is colorless and transparent, suitable designsmay be printed upon the uppermost sheet which designs will be clearlyvisible through the coating of the cellulose ester. -This gives a simpleand eifective means ofimitating the grain of wood.

'A very desirable product will be made if a natural or synthetic resinsuch as bakelite is added to the bath. The process is carriedlout inexactly the same manner as described above for the phenol or othercondensation product is converted to the hard, infusible, insolublecompound at the same time that the cellulose acetate is fused under theheat and pressure. The amount of phenol con- .densation product that maybeadded varies and I have found that as high a ratio as fifty parts ofphenol condensation product to fifty parts of cellulose acetate issatisfactory.

Modifying agents such as starch, glue, oils, camphor or naphthalene, andfilling materials such as zinc oxide, soapstone orcarbon 1 black maybeadded to the bath'and thus be incorporated in the laminated product. Ihavealso found that the addition of suitable ester will result in thecoloring of the product as desired.

,90 dyes to the solvent containing the cellulose The above describedmaterial is available for a wide variety of uses, such as a rawmaterialfrom which machine elements such as gears, pulleys, or the likemay be formed or machined and also asan electrical insulator, especiallyin the construction of switchboards for radio apparatus, a material formaking.

containers, or other structures which it is desirable shallbe unaffectedby moisture, oil

or other liquids. -It is also applicable for the surface veneering ofwood or cardbpard.

It will be understood-that the above described products may be built up,molded,

machined or otherwise formedin'to any ,de-

sired shapes, slnce its nature 1s such as to lend itself with peculiarfacility to these operations.

. I claim:

1. The process of making laminated material which comprises passingfibrous sheets through a solution of cellulose ester, thereafterevaporating the solvent and dryin the sheet and then superimposing theried sheets one upon the other to obtain the thickness desired, andthereafter heating the sam under ressure.

2. e process of makinglaminated mate- -rial which comprises passingfibrous sheets ness desired, and thereafter heating the same 20 underpressure.

\ JAMES MCINT OSHU

